The electrocardiogram (ECG) has proven over the years to be the single most effective clinical record for the diagnosis of cardiac muscle and cardiac nervous conduction abnormalities. An electrocardiogram is routinely taken not only on patients suspected of having cardiac disease, but also on normal patients to establish base line cardiac data. Thus, millions of ECG tracings are recorded yearly in private physicians' offices and in hospitals. It is imperative that these tracings be reliable and also that they be obtained rapidly to minimize the cost. It is to these objectives that the present invention is directed.
Generally, the ECG is usually comprised of twelve distinct records (i.e., tracings) which are obtained from a combination of specific electrical signals obtained from the body of the patient. These signals result from the heart's electrical activity which is conducted throughout the body. The signals, ordinarily in the millivolt range, may be sensed by metal electrodes making electrical contact with the body by way of electrically conductive electrode paste. The signals are transmitted from the electrodes through cables to an electrocardiograph or ECG recorder which includes amplifying circuitry, a heat stylus writing mechanism and switching circuitry. The latter circuitry permits combining the signals ordinarily taken from ten different positions on a patient's body to obtain the twelve tracings ordinarily desired. The twelve tracings, ordinarily adequate to obtain the heart's full spectrum of electrical data, are obtained from electrodes placed on the patient's four extremities and six electrodes carefully positioned on the precordium (i.e. the chest wall of the heart area). The latter six electrodes in the precordial positions are designated as V.sub.1, V.sub.2, V.sub.3, V.sub.4, V.sub.5 and V.sub.6. In certain cases, other positions on the chest may be chosen (e.g. V.sub.3 R) so that the specific example using positions V.sub.1 to V.sub.6 is illustrative rather than limiting.
The usual practice is to apply the electrodes to the arms (LA, RA), legs (LL, RL) and precordium (V.sub.1, V.sub.2, V.sub.3, V.sub.4, V.sub.5 and V.sub.6), with the electrodes being of a clamp type, sucton cup type or adhesive type. Such electrodes must be applied one-at-a-time and, in the case of the precordial electrodes particularly, require careful placing at specific anatomical locations. Thus, the careful and time-consuming attention of a skilled nurse, technician or doctor is required.
In a preferred embodiment of the present invention, a chest piece includes a strip of stretchable material, with apertures therein for receiving electrodes. When inserted in the apertures, the spacing between the electrodes and the pattern thereof correspond to the relative proportional spacing of precordial anatomic positions preferred for electrocardiograph monitoring.
Advantageously, each electrode may be provided with flange portions for releasably gripping edges of the apertures, whereby the strip or some or all of the electrodes may be replaced without replacement of the entire chest piece.
Each electrode may include a cup shaped member for containing electrolyte to be placed against the chest of the patient. Advantageously, the electrolyte may be introduced into the cup shaped member through the upper end of a tubular member. The tubular member may carry a terminal for electrical connection to the electrocardiograph machine. The terminal may be rotatable to facilitate electrical contact upon replacement of an electrode since the electrode has no preferred orientation when located in the stretchable strip.
The electrocardiograph electrode assembly may also include a retainer or holder means for engaging the ends of the stretchable strip and for stretching the strip a selectable amount to position and maintain the electrodes in contact witn precordial anatomic positions on the chest of the patient. Advantageously, the holder may be releasably attached to strip end members of the chest piece, which are themselves detachably coupled to the stretchable strips. For example, the holder may include a buckle adapted to engage a buckle catch formed in a strip end member of the chest piece. The strip end member may be detachably coupled to an end of the stretchable strip by snap fasteners thereby facilitating replacement of the stretchable strips without discarding of the strip end member and the associated buckle catch.
In one embodiment, the holder may include a pair of belts adapted for releasable attachment to opposite ends of the stretchable strip. At least one of the belts may be threaded through a base member located behind the patient. By pulling the belts, the chest piece may be quickly and easily stretched to properly position the electrodes and insure that the electrodes make sufficient tight contact with the patient's chest.
In another embodiment, the retainer may take the form of one or more weights for exerting a downward force on ends of the stretchable strip along the sides of the patient's chest. Such an arrangement is particularly suited to monitoring patients lying on a horizontal surface by permitting employment of the electrode assembly without the necessity of placing a holder or retainer behind the patient.
In still another embodiment, the retainer may overlie the chest of the patient and thus obviate the necessity of moving the patient.
It is accordingly an object of the present invention to provide novel and improved method and apparatus for rapidly applying electrocardiograph electrodes to a patient's body in clinically acceptable anatomic regions.
Another object of the invention is to provide novel and improved method and means for applying the precordial electrodes simultaneously and in clinically acceptable anatomic areas on the patient's chest despite a wide range of chest sizes and configurations.
A further object of the invention is to provide novel and improved method and means for applying precordial electrodes in clinical acceptable positions on a patient's chest while facilitating the connection of the leads to the electrocardiograph equipment.
Still another object of the present invention is to provide a novel stretchable chest piece adapted for positioning electrodes.
Yet still another object of the present invention is to provide a novel electrode for electrocardiograph monitoring.
Yet a further object of the present invention is to provide a novel method and apparatus for stretching the chest piece of the present invention across the chest of a patient without the necessity for moving the patient to place a holding means behind him.
These and other objects of the present invention will become apparent from the claims and from the following description when read in conjunction with the appended drawings.